Presentation "tropical deserts of Africa". Presentation "Deserts of Africa" ​​presentation for a geography lesson (grade 7) on the topic Presentations on the topic of African deserts

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• The Sahara is the greatest desert in the world.
• The word “Sahara” is associated with images of endless, glowing sand dunes with very rare emerald green oases. But in reality, here, in the vast expanses of the Sahara, you can find almost any type of desert landscape. In the Sahara, in addition to sand dunes, there are barren rocky plateaus strewn with stones; there are unusual fantastic geological formations; You can also see thickets of thorny bushes.

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• The Sahara is the greatest desert on Earth and occupies 30% of the area of ​​all of Africa. And this is half the territory of Russia, or the size of Brazil, the fifth largest country in the world.
• There are ten countries in the Sahara: Egypt, Algeria, Tunisia, Libya, Western Sahara, Mauritania, Niger, Morocco, Chad and Sudan.

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• Local residents also call it “The Sea without Water”, because 5-10 thousand years ago there were many lakes, rivers and tropical forests.
• Interestingly, the dunes of the Sahara move at speeds from a few centimeters to hundreds of meters per year, reaching a height of 250 m.

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The average daily temperature in the desert is +40 ° C, but during the day the sand sometimes warms up to +80 ° C. And at night the temperature can drop sharply to -15.

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Rain in the Sahara

Rain in the Sahara is a very rare holiday. But there are frequent sandstorms caused by hot desert winds. Over the past 50 years, the number of sandstorms has increased by 10, and in some places by 40 times.

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Population

Now 2.5 million people live in the Sahara. However, it used to be busier here. Caravans of traders often stretched across the Sahara, carrying gold, copper, slaves, and ostrich feathers. Just imagine, crossing the desert and back took 1.5 years!

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Fauna of the Sahara

• The fauna of the Sahara has 4 thousand species.
• Camels can live without water for two weeks, and without food for up to a month. These amazing animals can smell moisture from another 50 km away and can drink about 100 liters of water at a time. The interesting thing is that in such heat, camels do not sweat at all. Their large humps are fat, which allows the animals to go for a long time without food.

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sand cat

The sand cat is the smallest representative of wild cats. Body length is only 65-90 cm, 40% of which is the tail. These babies are nocturnal, escaping the heat of the day in burrows.

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Ethiopian hedgehog

Another striking representative of the fauna of the Sahara is the Ethiopian hedgehog. By the way, he can go without food for up to 2.5 months.

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fennec

Little fennec fox, the smallest fox in the world, also lives in the Sahara.

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Oryx

The body temperature of oryxes can reach 45 ° C. Despite their good endurance (they can go without water for a long time), the Ooryxes are now facing complete extinction.

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Kalahari Desert

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The Kalahari is called a desert, although it is more like a semi-desert because its average annual rainfall is significantly higher than what would normally fall in a true desert. This is a plateau with an almost uniform topography.

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The Kalahari Desert, the largest of the deserts in South Africa, covers an area of ​​about 600 thousand square meters. km, and its territory extends into Botswana, South Africa and Namibia. Recently, due to an increase in area, it has been invading the territory of Angola, Zimbabwe and Zambia.

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Climate of the Kalahari

The climate of the Kalahari is arid with summer maximum precipitation and mild winters, with aridity increasing towards the southeast. The Kalahari is one of the hottest regions of South Africa. Precipitation (up to 500 mm) is confined to the summer period (November - April), but its value varies significantly both in time and area.

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The average maximum temperature is plus 29 °C, and the average minimum temperature is plus 12 °C, evaporation is 3 thousand mm/year. In the Kalahari territory there is the largest delta in the world of the Okovango River, which does not flow anywhere.

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Surface of the Kalahari

The surface of the Kalahari is composed of Tertiary and Quaternary horizontally lying continental strata (Karru layers) of sandstones, pebbles and breccias.

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The entire territory of the Kalahari is occupied by sand dunes, located, as a rule, in chains at a distance of 70-150 m from each other. The accumulation of longitudinal dunes - alab - is especially common in the vicinity of the Molopo and Kuruman rivers. There are several types of Kalahari sands here. The most common are red sands, the color of which can vary from bright pink to red to almost brown, due to the presence of iron oxides.

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The soils are mainly red-brown and orange-brown, sandy, structureless, consisting mainly of coarse and fine sand, slightly acidic, with low fertility, which is caused by a lack of nitrogen and phosphorus. With depth, the color in more humid areas changes to yellow-brown, and the sand becomes denser.

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Giraffe

The giraffe is the tallest animal in the world. His height is approximately equal to the height of a two-story house. An adult male can reach a height of 6 m and weigh from 550 to 1800 kg.

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Zebra

Zebra (Equussp.) Zebras are a type of wild horse. All zebras have the same type of coloring - black and white stripes, but they depend on where they live: northern zebras have black and long stripes, southern zebras have brown and short stripes.

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Cheetah

The cheetah is the fastest land mammal: in a short time it can reach speeds of up to 112-120 km/h (70 to 75 mph) and can accelerate to almost 100 km/h in three seconds. This is one of the few members of the cat family with semi-retractable claws

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a lion

The lion is the second largest living cat after the tiger - some males can weigh up to 250 kg

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Cobra

The cobra poses an undoubted danger to humans and animals, but unlike viper snakes it always warns of its presence. Only in case of an immediate threat does the cobra make several lightning-fast attacks towards the enemy, one of which, as a rule, ends with a targeted bite

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Namib Desert

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The only place where you can cut down trees that died a thousand years ago is the Namib Desert in Africa.

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The Namib Desert is a coastal desert in southwestern Africa. The area of ​​the Namib is over 100 thousand sq. km. The desert stretches 1900 km along the Atlantic coast from the city of Namibe in Angola, across the whole of Namibia

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The South Atlantic blocks the path of the sandy waves of the Namib Desert, which stretches 2,000 km along the African coast.

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An endless sea of ​​sand dunes goes deep into the mainland, to the dry heart of the Namib Desert. At first glance, very few animals and plants live in this dry climate, however, just a sprinkle of rain, and the desert suddenly wakes up and a bright and active life begins.

Geographical location The space from the Atlantic Ocean to the Red Sea and from the foot of the Atlas Mountains and the Mediterranean coast to the northern borders of the savannas, occupied by tropical deserts, is called the Sahara. In South Africa, the desert zone occupies the Atlantic coast. This is where the Namib Desert is located.

Climate The annual precipitation in the Sahara is less than 50 ml. In the interior parts of the desert there is sometimes no rain for several years. Clouds are a rare phenomenon, so the sun's rays heat the earth's surface especially strongly. In summer, the daytime heat reaches + 40 C in the shade.

Flora The vegetation of the Sahara is extremely sparse, and in some places, especially in the central part, it is completely absent. Here and there isolated tufts of grasses and thorny bushes grow. Desert plants have a highly developed root system, with which they collect water from great depths and from vast spaces (for example, camel thorn). Many plants have very small leaves to reduce evaporation, and sometimes spines grow instead of leaves. Some plants appear only after rain and grow unusually quickly, bloom and bear fruit, and then dry out. Lichens are common in the rocky desert, and saltwort and wormwood are common on saline soils.

Flora The Namib Desert is characterized by a peculiar Welwitschia plant. Its short thick trunk rises above the ground only 50 cm. Two dense leathery leaves extend from its top, reaching a length of up to 3 m. The leaves grow continuously from the stem, dying off gradually at the ends. The age of Velvichia can exceed 150 years. The deserts of South Africa to the east and north turn into semi-deserts, where prickly cushion-shaped plants predominate, as well as milkweed, aloe, and wild watermelons with juicy fruits, which often replace water for the local population and animals.

Fauna Animals of the Sahara are adapted to desert climate conditions. Thus, antelopes are capable of running long distances in search of water and food. Lizards, turtles and snakes can go without water for a long time. Various beetles, locusts, and scorpions are also numerous. On the outskirts of the desert there are hyenas and lions.

Soils In deserts, due to the poor vegetation cover, there is very little organic matter in the soil. Desert tropical soils form here. They contain very little humus, but clay deserts contain mineral salts necessary for plant life. Due to the lack of rain, the salts are not washed out. Large areas of rocky and sandy deserts are devoid of soil cover.

Economic activities of people In the conditions of a tropical desert climate, agriculture in the Sahara is possible only in oases. Therefore, the local population is mainly engaged in animal husbandry and leads a nomadic lifestyle, raising goats, sheep and camels. Nomads live in large tents - tents covered with coarse woolen fabric or sheep and goat skins.

Sources V.A. Korinskaya, L.D. Prozorov, V.A. Shchenov. Geography textbook for 7th grade. Moscow education Kondratyev B.A., Matreveli P.M. Geography lessons: 6th grade. – Education, 1990 Photo gallery “Animal World” - thematic selection and software shell Absolut soft, 2002